noun
Shaku Nihongi
A late 13th-century commentary on the Nihon Shoki (日本書紀). This is a proper noun referring to a specific historical work.
釈日本紀は、日本書紀の注釈書として知られている。
The Shaku Nihongi is known as a commentary on the Nihon Shoki.
The Nihon Shoki is the original chronicle; 釈日本紀 is a commentary on it.
The title combines 釈 (explanation, commentary) with 日本紀 (an alternate name for the Nihon Shoki). The exact derivation is straightforward from the components.